The invention concerns a conveying device in a harvesting machine for harvesting in particular stem-bearing crops such as wood, maize, sugar cane, cereals, grass, rushes and hemp. The embodiment of the invention is described as applied to a forage harvester whose pick-up means are designed for harvesting fast-growing woody plants. This device is equipped with at least two counterrotatable circular blades for cutting down the crop material and a corresponding number of rotatable cylindrical housings which are arranged above the circular blades and which each comprise at least one pick-up element for fixing conveying tines.
With forage harvesters equipped in this way, fast-growing woody plants, such as willow and the like, may be harvested and chopped. The tines fixed to the rotatable housings are necessary so that the crop material, which is for example 3 to 5 m. high, is fed with the cut end in front to the conveying zone of the chopper. For this purpose the rotatable housings are normally driven in the same direction of rotation as the circular blades underneath. The directions of rotation are here selected such that the cut-off crop material is passed through the region between the two tined rotors.
A forage harvester shown in German Patent 196 27 872 A1, has tines bolted to a ring flange which is fixed to a rotatable housing. This housing is driven by a chain drive which, in turn, is driven by an engine. The housing and the tines are at an angle to the horizontal from the front region of the forage harvester. The circular blades underneath are also at an angle to the horizontal, the angle formed with the horizontal being smaller. The distance between the tines and the circular blades is relatively large, so that the cut-off ends of the stems are lifted and transported into the conveying zone. So that the tines can spring relative to the fixed ring flange, they are multiply wound in the fashion of a coil spring adjacent the fixing end. As a result there is a certain resiliency which however is not sufficient to prevent breaking in case of a load increased above the normal load, for example. This sometimes happens when there is an accumulation of crop material. The drive for the tines is reversible, so that in such cases the direction of rotation can be reversed to transport the crop material in the direction opposite the normal direction of flow. After a tine breaks it is necessary to change it, so that the chopper must be stopped temporarily. In spite of the resilient arrangement of the tines the service life is relatively short.